Vintage J-Model Whizzer

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Apr 3, 2011
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#91
Thanks, Mike!

By the way, concerning the engine test stand, I should mention that the major inspiration for this came from forum-member "Dirt Nerd", who is restoring his dad's original Whizzer, and doing a fantastic job. Here' is his test setup:



If you haven't checked out Dirt Nerd's restoration thread, do so. It's very well documented with lots of pictures. A great inspiration!

Paula
 
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Joined
Apr 23, 2012
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#92
Awwww, shucks, Paula. One thing we share is that big distraction called 'the job'. Glad you liked the stand. Your thread is KING in my book.

I haven't updated in a while, but starting to put the bike together - guess i should head over to my build thread to update the group.

Don't forget - make time away from work to play in the garage - it's where we can all think freely.

paul
 
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#93
Don't forget - make time away from work to play in the garage - it's where we can all think freely.

paul
Sage advice, indeed! I took a week off from work recently and managed to get a lot of "playing" done in the shop.


Time to start fabricating the fuel tank brackets for the test stand. I had an idea to make them from some rectangular steel tubing that I dug out of the scrap bin at work. The first step was to cut the tubing to the required length:



Next, a 1" hole was drilled as a starter hole for the fuel tank filler cutout:



The drilled hole was then enlarged to final size using the boring head:



An end mill was used to finish the ends of the cutout:



After drilling a couple small holes for the fuel tank mounting screws, it was back to the cutoff saw:





Following the above cuts, some angle cuts were made to finish the shaping of the part. The lower bracket was completed in a similar fashion. The remaining parts for the test stand (throttle control bracket, and mounting bracket) were simple and straightforward, so no pictures were taken. On to the welding phase...

First step was welding a cap on the angled end of the vertical tube. Here's what it looked like after some grinding and sanding to finish off the rough edges:



The upper fuel tank bracket and vertical tube were positioned and clamped to the top of the welding cart. Two quick welds on either side of the bracket were enough to finish that part of the job:



To correctly position the lower bracket for welding, the fuel tank was bolted to the upper bracket:



The rest of the welding phase was uneventful. Here is the completed bracket weldment, ready for priming and paint:



To mount the finished bracket weldment to the engine stand, a couple of holes need to be located, drilled, and tapped in the side of the frame:



Stay tuned, there's more to come...
 
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#94
Starter Clutch

As mentioned in an earlier post above, I wanted to come up with a suitable means of starting the engine whilst it is mounted in the test stand. I had already rejected the hex-socket-on-the-flywheel-bolt method as being a bit too risky, and the pony motor idea as too elaborate and space-consuming. What I finally arrived at is a simple type of self-ejecting clutch. It consists of two parts: 1) a male driver, which is basically a 1/2" dia. shank, cross-drilled for a 3/16 dowel pin, and 2) a female-headed driven bolt with two helical cutouts, which replaces the standard 3/8-24 LH flywheel bolt.

Here's a CAD view showing the clutch at full engagement:



When the engine starts up, exceeding the speed of the drill, the driver half is automatically disengaged:



Due to the amount of torque being transmitted when the clutch is in operation, I wanted to use a high-strength steel to make the parts. I ended up using a special grade of 4140 steel sometimes referred to as "ETD-150". The 'ETD' stands for Elevated Temperature Drawn, and I believe that the '150' refers to (nominally) 150,000 psi tensile strength. It's listed as having a yield strength of 130,000 psi, which is 2-3 times that of regular 1018 cold rolled steel. I have used this steel before on other projects, and it machines like a dream. Very nice stuff to work with.

Here's a quick rundown of the machining process:

After cutting the stock to length, one end is turned down to .500" dia. This will end up being the 3/8-24 LH threaded shank, but for now the .500" simplifies the head machining operations:



The part is then flipped around for the turning operations on the O.D. of the head:



A 33/64" hole is drilled in the head. This provides a nice working clearance for the 1/2" dia. driver shank:



At this point the part is removed from the lathe, and mounted in a 6-sided 5C collet fixture. This type of fixture is useful for machining hex flats on a round part. Once the mill is setup to cut one flat, the fixture is simply repositioned in the vise to cut the next flat:



Next, the part is transferred to a 4-sided 5C collet fixture for machining the two helical cutouts. First step here is to drill and ream a 13/64" cross hole, providing an easy way to align the mill's spindle to the part for milling the helical cutouts:



The vise is then rotated to an angle of 48.5 degrees. The spindle is centered over the previously reamed hole, and then a 33/64 end mill is used to finish the first cutout. The 5C fixture is then flipped over for the second cutout:



The final step for this part is to chuck the head in the lathe and cut the 3/8-24 left-hand thread:



The driver (male portion of the clutch) is a simple part to make, so I didn't take pictures of the operations. It's just a 1/2" dia. piece of ETD-150, cross-drilled on one end for a 3/16" dowel pin, LocTited in place. I cut three flats on the opposite end to keep it from slipping in the drill chuck.

Here's a look at the finished starter clutch parts on the engine:



Almost ready to try starting 'er up!
 
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#95
Test Running the Engine

Well, the moment of truth has arrived...

With the engine test module completed, it's time to try starting this engine that has taken so long to finish. I think everything is just about ready. I've mounted the engine stand to a heavy steel cart (my "welding cart") for the test run. I bolted the stand to a couple short lengths of 3/8 x 1-1/4" steel which are C-clamped to the cart. Here's the setup:



The throttle control is just one of those generic aftermarket units. I shortened the cable as needed to do the job. Since it's so short, there's no need to anchor the end of the cable housing. The fuel filter unit is the one that came with the bike, sporting a new screen and gasket. The fuel hose is new.

The temporary muffler is another generic replacement unit with a 3/4" pipe thread. I found that with a bit of judicious filing on the tapered threads, it was a nice slip fit in the Whizzer exhaust elbow. I did, however, have to make a 1/4" thick spacer for the exhaust elbow so that the muffler would clear the cylinder:



I double-checked the timing (30 degrees BTDC), filled the crankcase with Valvoline straight 30-weight, and put some gasoline in the tank. Opened the valve on the fuel filter, and waited to see if any gas leaked from the carb... nope, the needle valve and float must be working ok. I set up a fan to blow air across the engine to keep it from getting too hot.

I set the choke at about 3/4 closed, and the throttle at about 1/3 open. My Milwaukee electric drill was used to drive the starter clutch. With only a few turns of the flywheel, the engine roared to life! I was surprised at how quickly it started! After letting it warm up for a while, I made some carburetor adjustments. So far, everything seems fine -- no leaks, no strange noises. It runs!! Wow, this thing is hairy!!



After playing around with it for a while, I set up the camera for the obligatory video. Here's a short clip showing start-up, idling, and several menacing throttle bumps:



Thanks to all who offered advice and encouragement! On to the next phase of the project...

Paula
 
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Quenton Guenther

Motored Bikes Sponsor
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#96
Hi Paula,

Fantastic!

Been a real treat watching world class machine work on a vintage Whizzer motor. Just want to offer a suggestion concerning your motor & oil. If you install the tall oil breather used on the later motors you can add 2 more ounces of oil [a really good thing]. The later motors held 8 ounces of oil instead of 6 ounces. Of course, you most likely would make your own, and it isn't a simple as extending the current version, as some of the parts at the bottom are different. If you decide to make the upgrade, and need pictures or any information, I can easily provide them.

Thanks again for a great post

Have fun,
 
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#97
Thanks Quenton! Coming from you, I consider that high praise indeed.

Thanks for the advice about the taller oil breather... I'll definitely give that some thought. I've seen the repro units on eBay, but that seller has had some quality issues. Might take some re-work.


Paula
 

Quenton Guenther

Motored Bikes Sponsor
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#98
Hi Paula,

Sadly the current repros are not even close to the originals, as the aluminum is much thinner and they have a rough surface. Same is true of the latest batch of magneto covers. I have several of the original tall breathers if you need to borrow one for a pattern [If you decide to make one].

Once again, thanks for the great post.

Have fun,
 
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#99
Quenton, I really appreciate that offer! I'd love to borrow an original breather to examine.

I'll P.M you with the particulars...

Thanks!

Paula
 
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Rec'd the tall breather in the mail today... THANKS, Quenton!

I will check it out, and let you know which way I decide to go.

Paula
 
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